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It took me a lot of effort to get signal tap to actually pick something up, but when I finally did, I noticed all of the signals looked good. I then turned around and looked at the screen, and behold, the characters written to memory was displayed. Only problem is, I can't get it to work without signal tap, so I'm at a loss as to what's going on. Any ideas?
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This stuff will drive you nuts sometimes. The only thing I can think here is that one or more signals are getting optimized out without SignalTap, but when they are instrumented in SignalTap they do not get optimized out. I assume that in SignalTap you selected nets "pre-synthesis"?
If anything is getting optimized out it should be mentioned in the reports, but it sounds like you're not seeing anything? If that's the case then it might be worth trying the netlist viewers (Tools -> Netlist Viewers) to make sure everything is hooked up properly. You can look at the rtl viewer or post-map or post-fit. Try compiling without SignalTap and then find your VRam in the post-map viewer and see if it's connected correctly.
If you simply can't figure this out then it's time for a service request. That can be a frustrating process, but if you're able to send them an archived project they should be able to figure it out for you.
Good luck. Please post back with whatever you find out (hopefully with the problem resolved).
Bob
Honored Contributor
